1. Field
Methods and apparatuses consistent with the exemplary embodiments relate to a monitoring camera, and more particularly, to a monitoring camera for generating a 3-dimensional (3D) image and a method of generating a 3D image by using one monitoring camera.
2. Description of the Related Art
Monitoring cameras are widely used for security or crime prevention. Mostly, one monitoring camera is installed for surveillance. Thus, a 2-dimensional (2D) image captured by the monitoring camera is displayed on a monitor. The monitoring camera may monitor surroundings while performing a pan operation for rotating 360° in a horizontal direction, a tilt operation for rotating 90° in a vertical direction, and a zoom operation for expanding or reducing the size of an object.
In order to generate three-dimensional (3D) distance information, stereo vision using two cameras is required. In other words, when one monitoring camera is used, a 2D image is displayed on a screen since 3D information about a surveillance space and object cannot be generated despite that an actual surveillance space is 3D. Thus, the 2D image is discordant with a geometrical structure of the actual surveillance space when a function such as a privacy mask, or a pan, tilt, or zoom operation is performed.
This is because the monitoring camera generates 2D image information by using a plane charge-coupled device (CCD) sensor, and thus, 3D information is lost as image information in a 3D space is projected in 2D.
Examples of 3D information about an object include a distance between an object and a camera, a distance between an object and a background, and information about whether an object is spatially moving towards or away from a camera.
Since a monitoring camera in the related art cannot use distance information between an object and a background, i.e., 3D spatial information about an image being captured, a desired performance cannot be obtained while realizing a basic function, such as privacy mask. In other words, the related art monitoring camera monitors in 2D without recognizing a 3D space, such as a close object, a far object, an approaching object, a receding object, a close background, or a far background, and thus, distortedly recognizes a big object, a small object, an object increasing in size, an object decreasing in size, a big background, or a small background.
Such a spatial recognition may not be generated in a fixed monitoring camera instead of a pan-tilt-zoom (PTZ) camera. However, in the PTZ camera performing operations such as up-down-right-left movement, expansion, and reduction, the loss of 3D information in a surveillance area may cause problems.